drm/virtio: free virtqueues on probe failure

We should call virtio_gpu_deinit() to free virtqueues when
drm_dev_register() failed.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210517084913.403-3-xieyongji@bytedance.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>